Reference point determination

ABSTRACT

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may receive, from a base station and based at least in part on a triggering event, an indication of a frequency domain indexing configuration for a relative reference point. The user equipment may use at least one of a start of a control resource set or an absolute reference point for the relative reference point based at least in part on the indication of the frequency domain indexing configuration. Numerous other aspects are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS UNDER 35 U.S.C. § 119

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/657,555, filed on Apr. 13, 2018, entitled “TECHNIQUES ANDAPPARATUSES FOR REFERENCE POINT DETERMINATION,” which is herebyexpressly incorporated by reference herein.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wirelesscommunication and to techniques and apparatuses for reference pointdetermination.

BACKGROUND

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power, etc.). Examples of such multiple-access technologiesinclude code division multiple access (CDMA) systems, time divisionmultiple access (TDMA) systems, frequency-division multiple access(FDMA) systems, orthogonal frequency-division multiple access (OFDMA)systems, single-carrier frequency-division multiple access (SC-FDMA)systems, time division synchronous code division multiple access(TD-SCDMA) systems, and Long Term Evolution (LTE). LTE/LTE-Advanced is aset of enhancements to the Universal Mobile Telecommunications System(UMTS) mobile standard promulgated by the Third Generation PartnershipProject (3GPP).

A wireless communication network may include a number of base stations(BSs) that can support communication for a number of user equipment(UEs). A user equipment (UE) may communicate with a base station (BS)via the downlink and uplink. The downlink (or forward link) refers tothe communication link from the BS to the UE, and the uplink (or reverselink) refers to the communication link from the UE to the BS. As will bedescribed in more detail herein, a BS may be referred to as a Node B, agNB, an access point (AP), a radio head, a transmit receive point (TRP),a New Radio (NR) BS, a 5G Node B, and/or the like.

The above multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent user equipment to communicate on a municipal, national,regional, and even global level. New Radio (NR), which may also bereferred to as 5G, is a set of enhancements to the LTE mobile standardpromulgated by the Third Generation Partnership Project (3GPP). NR isdesigned to better support mobile broadband Internet access by improvingspectral efficiency, lowering costs, improving services, making use ofnew spectrum, and better integrating with other open standards usingorthogonal frequency division multiplexing (OFDM) with a cyclic prefix(CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and/or SC-FDM (e.g.,also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) onthe uplink (UL), as well as supporting beamforming, multiple-inputmultiple-output (MIMO) antenna technology, and carrier aggregation.However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in LTE and NRtechnologies. Preferably, these improvements should be applicable toother multiple access technologies and the telecommunication standardsthat employ these technologies.

SUMMARY

In some aspects, a method of wireless communication, performed by a userequipment (UE), may include receiving, from a base station and based atleast in part on a triggering event, an indication of a frequency domainindexing configuration for a relative reference point; and using atleast one of a start of a control resource set or an absolute referencepoint for the relative reference point based at least in part on theindication of the frequency domain indexing configuration.

In some aspects, a UE for wireless communication may include memory andone or more processors operatively coupled to the memory. The memory andthe one or more processors may be configured to receive, from a basestation and based at least in part on a triggering event, an indicationof a frequency domain indexing configuration for a relative referencepoint; and use at least one of a start of a control resource set or anabsolute reference point for the relative reference point based at leastin part on the indication of the frequency domain indexingconfiguration.

In some aspects, a non-transitory computer-readable medium may store oneor more instructions for wireless communication. The one or moreinstructions, when executed by one or more processors of a UE, may causethe one or more processors to: receive, from a base station and based atleast in part on a triggering event, an indication of a frequency domainindexing configuration for a relative reference point; and use at leastone of a start of a control resource set or an absolute reference pointfor the relative reference point based at least in part on theindication of the frequency domain indexing configuration.

In some aspects, an apparatus for wireless communication may includemeans for receiving, from a base station and based at least in part on atriggering event, an indication of a frequency domain indexingconfiguration for a relative reference point; and means for using atleast one of a start of a control resource set or an absolute referencepoint for the relative reference point based at least in part on theindication of the frequency domain indexing configuration.

Aspects generally include a method, apparatus, system, computer programproduct, non-transitory computer-readable medium, user equipment, basestation, wireless communication device, and processing system assubstantially described herein with reference to and as illustrated bythe accompanying specification and drawings.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the above-recited features of the present disclosure can beunderstood in detail, a more particular description, briefly summarizedabove, may be had by reference to aspects, some of which are illustratedin the appended drawings. It is to be noted, however, that the appendeddrawings illustrate only certain typical aspects of this disclosure andare therefore not to be considered limiting of its scope, for thedescription may admit to other equally effective aspects. The samereference numbers in different drawings may identify the same or similarelements.

FIG. 1 is a block diagram conceptually illustrating an example of awireless communication network, in accordance with various aspects ofthe present disclosure.

FIG. 2 is a block diagram conceptually illustrating an example of a basestation in communication with a user equipment (UE) in a wirelesscommunication network, in accordance with various aspects of the presentdisclosure.

FIG. 3A is a block diagram conceptually illustrating an example of aframe structure in a wireless communication network, in accordance withvarious aspects of the present disclosure.

FIG. 3B is a block diagram conceptually illustrating an examplesynchronization communication hierarchy in a wireless communicationnetwork, in accordance with various aspects of the present disclosure.

FIG. 4 is a block diagram conceptually illustrating an example subframeformat with a normal cyclic prefix, in accordance with various aspectsof the present disclosure.

FIG. 5 illustrates an example logical architecture of a distributedradio access network (RAN), in accordance with various aspects of thepresent disclosure.

FIG. 6 illustrates an example physical architecture of a distributedRAN, in accordance with various aspects of the present disclosure.

FIG. 7 is a diagram illustrating an example of reference pointdetermination, in accordance with various aspects of the presentdisclosure.

FIG. 8 is a diagram illustrating an example process performed, forexample, by a user equipment, in accordance with various aspects of thepresent disclosure.

DETAILED DESCRIPTION

In some communications systems, such as 5G or NR, a relative referencepoint for a frequency domain may be used to synchronize communication. AUE may communicate using a set of physical resource blocks allocated fora bandwidth part, and may identify the set of physical resource blocksbased at least in part on physical resource block indices. The UE mayuse the relative reference point to define resource allocationscorresponding to the physical resource block indices. For example, theUE may determine that a physical resource block (with an index of 0) isto occur based at least in part on a defined absolute reference point ofa communication structure. The UE may determine a configuration for aphysical resource block 0 of an initial downlink bandwidth part and/oran initial control resource set (CORESET) based at least in part on aphysical broadcast channel (PBCH). The UE may determine a configurationfor a physical resource block 0 of a bandwidth part at least in part onremaining minimum system information (RMSI) message.

However, some triggering events may result in an ambiguity in resolvingphysical resource block indexing in the frequency domain. For example,after a handover, the UE may determine an initial bandwidth part for acell, but the UE may not have information identifying whether aconfigured bandwidth part and/or CORESET resulting from the handover, isthe configured bandwidth part and/or CORESET for initial access. Thismay occur based at least in part on the UE determining the cell based atleast in part on the handover and not based at least in part on aninitial access procedure. As a result, the UE may incorrectly determinethe physical resource block indexing. Moreover, in some cases, the UEmay have a plurality of options for defining a relative reference point,such as an absolute reference point, based at least in part on aplurality of available cells (e.g., serving cells, neighbor cells,and/or the like). In this case, ambiguity in resolving an absolutereference point may result in a failure of radio resource managementmeasurements.

Some aspects described herein may enable reference point determination.For example, the UE may determine an indexing configuration for physicalresource block indexing based at least in part on receiving anindication from a BS. For example, the UE may receive an indication toconfigure physical resource block indexing based at least in part on astart of a CORESET (e.g., for localized physical resource block indexingspecific to the CORESET) or based at least in part on a defined absolutereference point (e.g., for global physical resource block indexing formultiple bandwidth parts and physical channels/signals). In someaspects, the UE may receive an indication identifying a configurationfor selecting an absolute reference point of a plurality of candidateabsolute reference point's. In this way, the UE may accurately resolve acommunication structure for communicating with the BS, thereby reducinga likelihood of a communication interruption and improving networkperformance relative to the UE having ambiguity and inaccuracy inresolving the physical resource block indexing and/or an absolutereference point used therein.

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. Based at least inpart on the teachings herein one skilled in the art should appreciatethat the scope of the disclosure is intended to cover any aspect of thedisclosure disclosed herein, whether implemented independently of orcombined with any other aspect of the disclosure. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, the scope of thedisclosure is intended to cover such an apparatus or method which ispracticed using other structure, functionality, or structure andfunctionality in addition to or other than the various aspects of thedisclosure set forth herein. It should be understood that any aspect ofthe disclosure disclosed herein may be embodied by one or more elementsof a claim.

Several aspects of telecommunication systems will now be presented withreference to various apparatuses and techniques. These apparatuses andtechniques will be described in the following detailed description andillustrated in the accompanying drawings by various blocks, modules,components, circuits, steps, processes, algorithms, etc. (collectivelyreferred to as “elements”). These elements may be implemented usinghardware, software, or combinations thereof. Whether such elements areimplemented as hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

It should be noted that while aspects may be described herein usingterminology commonly associated with 3G and/or 4G wireless technologies,aspects of the present disclosure can be applied in othergeneration-based communication systems, such as 5G and later, includingNR technologies.

FIG. 1 is a diagram illustrating a network 100 in which aspects of thepresent disclosure may be practiced. The network 100 may be an LTEnetwork or some other wireless network, such as a 5G or NR network.Wireless network 100 may include a number of BSs 110 (shown as BS 110 a,BS 110 b, BS 110 c, and BS 110 d) and other network entities. A BS is anentity that communicates with user equipment (UEs) and may also bereferred to as a base station, a NR BS, a Node B, a gNB, a 5G node B(NB), an access point, a transmit receive point (TRP), and/or the like.Each BS may provide communication coverage for a particular geographicarea. In 3GPP, the term “cell” can refer to a coverage area of a BSand/or a BS subsystem serving this coverage area, depending on thecontext in which the term is used.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or another type of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a closed subscriber group (CSG)). A BS for a macro cell may bereferred to as a macro BS. A BS for a pico cell may be referred to as apico BS. A BS for a femto cell may be referred to as a femto BS or ahome BS. In the example shown in FIG. 1, a BS 110 a may be a macro BSfor a macro cell 102 a, a BS 110 b may be a pico BS for a pico cell 102b, and a BS 110 c may be a femto BS for a femto cell 102 c. A BS maysupport one or multiple (e.g., three) cells. The terms “eNB”, “basestation”, “NR BS”, “gNB”, “TRP”, “AP”, “node B”, “5G NB”, and “cell” maybe used interchangeably herein.

In some examples, a cell may not necessarily be stationary, and thegeographic area of the cell may move according to the location of amobile BS. In some examples, the BSs may be interconnected to oneanother and/or to one or more other BSs or network nodes (not shown) inthe access network 100 through various types of backhaul interfaces suchas a direct physical connection, a virtual network, and/or the likeusing any suitable transport network.

Wireless network 100 may also include relay stations. A relay station isan entity that can receive a transmission of data from an upstreamstation (e.g., a BS or a UE) and send a transmission of the data to adownstream station (e.g., a UE or a BS). A relay station may also be aUE that can relay transmissions for other UEs. In the example shown inFIG. 1, a relay station 110 d may communicate with macro BS 110 a and aUE 120 d in order to facilitate communication between BS 110 a and UE120 d. A relay station may also be referred to as a relay BS, a relaybase station, a relay, etc.

Wireless network 100 may be a heterogeneous network that includes BSs ofdifferent types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc.These different types of BSs may have different transmit power levels,different coverage areas, and different impact on interference inwireless network 100. For example, macro BSs may have a high transmitpower level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relayBSs may have lower transmit power levels (e.g., 0.1 to 2 Watts).

A network controller 130 may couple to a set of BSs and may providecoordination and control for these BSs. Network controller 130 maycommunicate with the BSs via a backhaul. The BSs may also communicatewith one another, e.g., directly or indirectly via a wireless orwireline backhaul.

UEs 120 (e.g., 120 a, 120 b, 120 c) may be dispersed throughout wirelessnetwork 100, and each UE may be stationary or mobile. A UE may also bereferred to as an access terminal, a terminal, a mobile station, asubscriber unit, a station, etc. A UE may be a cellular phone (e.g., asmart phone), a personal digital assistant (PDA), a wireless modem, awireless communication device, a handheld device, a laptop computer, acordless phone, a wireless local loop (WLL) station, a tablet, a camera,a gaming device, a netbook, a smartbook, an ultrabook, a medical deviceor equipment, biometric sensors/devices, wearable devices (smartwatches, smart clothing, smart glasses, smart wrist bands, smart jewelry(e.g., smart ring, smart bracelet)), an entertainment device (e.g., amusic or video device, or a satellite radio), a vehicular component orsensor, smart meters/sensors, industrial manufacturing equipment, aglobal positioning system device, or any other suitable device that isconfigured to communicate via a wireless or wired medium.

Some UEs may be considered machine-type communication (MTC) or evolvedor enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEsinclude, for example, robots, drones, remote devices, sensors, meters,monitors, location tags, etc., that may communicate with a base station,another device (e.g., remote device), or some other entity. A wirelessnode may provide, for example, connectivity for or to a network (e.g., awide area network such as Internet or a cellular network) via a wired orwireless communication link. Some UEs may be consideredInternet-of-Things (IoT) devices, and/or may be implemented as NB-IoT(narrowband internet of things) devices. Some UEs may be considered aCustomer Premises Equipment (CPE). UE 120 may be included inside ahousing that houses components of UE 120, such as processor components,memory components, and/or the like.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular RAT andmay operate on one or more frequencies. A RAT may also be referred to asa radio technology, an air interface, etc. A frequency may also bereferred to as a carrier, a frequency channel, etc. Each frequency maysupport a single RAT in a given geographic area in order to avoidinterference between wireless networks of different RATs. In some cases,NR or 5G RAT networks may be deployed.

In some examples, access to the air interface may be scheduled, such asbased at least in part on a relative reference point, wherein ascheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within thescheduling entity's service area or cell. Within the present disclosure,as discussed further below, the scheduling entity may be responsible forscheduling, assigning, reconfiguring, and releasing resources for one ormore subordinate entities. That is, for scheduled communication,subordinate entities utilize resources allocated by the schedulingentity.

Base stations are not the only entities that may function as ascheduling entity. That is, in some examples, a UE may function as ascheduling entity, scheduling resources for one or more subordinateentities (e.g., one or more other UEs). In this example, the UE isfunctioning as a scheduling entity, and other UEs utilize resourcesscheduled by the UE for wireless communication. A UE may function as ascheduling entity in a peer-to-peer (P2P) network, and/or in a meshnetwork. In a mesh network example, UEs may optionally communicatedirectly with one another in addition to communicating with thescheduling entity.

Thus, in a wireless communication network with a scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, and a mesh configuration, a scheduling entity and one ormore subordinate entities may communicate utilizing the scheduledresources.

In some aspects, two or more UEs 120 (e.g., shown as UE 120 a and UE 120e) may communicate directly using one or more sidelink channels (e.g.,without using a base station 110 as an intermediary to communicate withone another). For example, the UEs 120 may communicate usingpeer-to-peer (P2P) communications, device-to-device (D2D)communications, a vehicle-to-everything (V2X) protocol (e.g., which mayinclude a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure(V2I) protocol, and/or the like), a mesh network, and/or the like. Inthis case, the UE 120 may perform scheduling operations, resourceselection operations, and/or other operations described elsewhere hereinas being performed by the base station 110.

As indicated above, FIG. 1 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 1.

FIG. 2 shows a block diagram of a design 200 of base station 110 and UE120, which may be one of the base stations and one of the UEs in FIG. 1.Base station 110 may be equipped with T antennas 234 a through 234 t,and UE 120 may be equipped with R antennas 252 a through 252 r, where ingeneral T≥1 and R≥1.

At base station 110, a transmit processor 220 may receive data from adata source 212 for one or more UEs, select one or more modulation andcoding schemes (MCS) for each UE based at least in part on channelquality indicators (CQIs) received from the UE, process (e.g., encodeand modulate) the data for each UE based at least in part on the MCSselected for the UE, and provide data symbols for all UEs. Transmitprocessor 220 may also process system information (e.g., for semi-staticresource partitioning information (SRPI), etc.) and control information(e.g., CQI requests, grants, upper layer signaling, etc.) and provideoverhead symbols and control symbols. Transmit processor 220 may alsogenerate reference symbols for reference signals (e.g., thecell-specific reference signal (CRS)) and synchronization signals (e.g.,the primary synchronization signal (PSS) and secondary synchronizationsignal (SSS)). A transmit (TX) multiple-input multiple-output (MIMO)processor 230 may perform spatial processing (e.g., precoding) on thedata symbols, the control symbols, the overhead symbols, and/or thereference symbols, if applicable, and may provide T output symbolstreams to T modulators (MODs) 232 a through 232 t. Each modulator 232may process a respective output symbol stream (e.g., for OFDM, etc.) toobtain an output sample stream. Each modulator 232 may further process(e.g., convert to analog, amplify, filter, and upconvert) the outputsample stream to obtain a downlink signal. T downlink signals frommodulators 232 a through 232 t may be transmitted via T antennas 234 athrough 234 t, respectively. According to various aspects described inmore detail below, the synchronization signals can be generated withlocation encoding to convey additional information.

At UE 120, antennas 252 a through 252 r may receive the downlink signalsfrom base station 110 and/or other base stations and may providereceived signals to demodulators (DEMODs) 254 a through 254 r,respectively. UE 120 may receive the downlink signals and/or provideuplink signals based at least in part on determining a relativereference point for a frequency domain physical resource block indexingconfiguration. Each demodulator 254 may condition (e.g., filter,amplify, downconvert, and digitize) a received signal to obtain inputsamples. Each demodulator 254 may further process the input samples(e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256may obtain received symbols from all R demodulators 254 a through 254 r,perform MIMO detection on the received symbols if applicable, andprovide detected symbols. A receive processor 258 may process (e.g.,demodulate and decode) the detected symbols, provide decoded data for UE120 to a data sink 260, and provide decoded control information andsystem information to a controller/processor 280. A channel processormay determine reference signal received power (RSRP), received signalstrength indicator (RSSI), reference signal received quality (RSRQ),channel quality indicator (CQI), etc.

On the uplink, at UE 120, a transmit processor 264 may receive andprocess data from a data source 262 and control information (e.g., forreports comprising RSRP, RSSI, RSRQ, CQI, etc.) fromcontroller/processor 280. Transmit processor 264 may also generatereference symbols for one or more reference signals. The symbols fromtransmit processor 264 may be precoded by a TX MIMO processor 266 ifapplicable, further processed by modulators 254 a through 254 r (e.g.,for DFT-s-OFDM, CP-OFDM, etc.), and transmitted to base station 110. Atbase station 110, the uplink signals from UE 120 and other UEs may bereceived by antennas 234, processed by demodulators 232, detected by aMIMO detector 236 if applicable, and further processed by a receiveprocessor 238 to obtain decoded data and control information sent by UE120. Receive processor 238 may provide the decoded data to a data sink239 and the decoded control information to controller/processor 240.Base station 110 may include communication unit 244 and communicate tonetwork controller 130 via communication unit 244. Network controller130 may include communication unit 294, controller/processor 290, andmemory 292.

In some aspects, one or more components of UE 120 may be included in ahousing. Controller/processor 240 of base station 110,controller/processor 280 of UE 120, and/or any other component(s) ofFIG. 2 may perform one or more techniques associated with referencepoint determination, as described in more detail elsewhere herein. Forexample, controller/processor 240 of base station 110,controller/processor 280 of UE 120, and/or any other component(s) ofFIG. 2 may perform or direct operations of, for example, process 800 ofFIG. 8 and/or other processes as described herein. Memories 242 and 282may store data and program codes for base station 110 and UE 120,respectively. A scheduler 246 may schedule UEs for data transmission onthe downlink and/or uplink.

The stored program codes, when executed by processor 280 and/or otherprocessors and modules at UE 120, may cause the UE 120 to performoperations described with respect to process 800 of FIG. 8 and/or otherprocesses as described herein. The stored program codes, when executedby processor 240 and/or other processors and modules at base station110, may cause the base station 110 to perform operations described withrespect processes as described herein. A scheduler 246 may schedule UEsfor data transmission on the downlink and/or uplink.

In some aspects, UE 120 may include means for receiving, from BS 110 andbased at least in part on a triggering event, an indication of afrequency domain indexing configuration for a relative reference point,and means for using at least one of a start of a control resource set oran absolute reference point for the relative reference point based atleast in part on the indication of the frequency domain indexingconfiguration, and/or the like. In some aspects, such means may includeone or more components of UE 120 described in connection with FIG. 2.

While blocks in FIG. 2 are illustrated as distinct components, thefunctions described above with respect to the blocks may be implementedin a single hardware, software, or combination component or in variouscombinations of components. For example, the functions described withrespect to the transmit processor 264, the receive processor 258, and/orthe TX MIMO processor 266 may be performed by or under the control ofprocessor 280.

As indicated above, FIG. 2 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 2.

FIG. 3A shows an example frame structure 300 for FDD in atelecommunications system (e.g., NR). The transmission timeline for eachof the downlink and uplink may be partitioned into units of radioframes. Each radio frame may have a predetermined duration and may bepartitions into a set of Z (Z≥1) subframes (e.g., with indices of 0through Z−1). Each subframe may include a set of slots (e.g., two slotsper subframe are shown in FIG. 3A). Each slot may include a set of Lsymbol periods. For example, each slot may include seven symbol periods(e.g., as shown in FIG. 3A), fifteen symbol periods, and/or the like. Ina case where the subframe includes two slots, the subframe may include2L symbol periods, where the 2L symbol periods in each subframe may beassigned indices of 0 through 2L−1. In some aspects, a scheduling unitfor the FDD may frame-based, subframe-based, slot-based, symbol-based,and/or the like.

While some techniques are described herein in connection with frames,subframes, slots, and/or the like, these techniques may equally apply toother types of wireless communication structures, which may be referredto using terms other than “frame,” “subframe,” “slot,” and/or the likein 5G NR. In some aspects, a wireless communication structure may referto a periodic time-bounded communication unit defined by a wirelesscommunication standard and/or protocol. Additionally, or alternatively,different configurations of wireless communication structures than thoseshown in FIG. 3A may be used.

In certain telecommunications (e.g., NR), a base station may transmitsynchronization signals. For example, a base station may transmit aprimary synchronization signal (PSS), a secondary synchronization signal(SSS), and/or the like, on the downlink for each cell supported by thebase station. The PSS and SSS may be used by UEs for cell search andacquisition. For example, the PSS may be used by UEs to determine symboltiming, and the SSS may be used by UEs to determine a physical cellidentifier, associated with the base station, and frame timing. The basestation may also transmit a physical broadcast channel (PBCH). The PBCHmay carry some system information, such as system information thatsupports initial access by UEs. The BS may determine a configuration forphysical resource block indexing based at least in part on whether acomponent carrier includes an SS/PBCH block.

In some aspects, the base station may transmit the PSS, the SSS, and/orthe PBCH in accordance with a synchronization communication hierarchy(e.g., a synchronization signal (SS) hierarchy) including multiplesynchronization communications (e.g., SS blocks), as described below inconnection with FIG. 3B.

FIG. 3B is a block diagram conceptually illustrating an example SShierarchy, which is an example of a synchronization communicationhierarchy. As shown in FIG. 3B, the SS hierarchy may include an SS burstset, which may include a plurality of SS bursts (identified as SS burst0 through SS burst B−1, where B is a maximum number of repetitions ofthe SS burst that may be transmitted by the base station). As furthershown, each SS burst may include one or more SS blocks (identified as SSblock 0 through SS block (b_(max_SS-1)), where b_(max_SS-1) is a maximumnumber of SS blocks that can be carried by an SS burst). In someaspects, different SS blocks may be beam-formed differently. An SS burstset may be periodically transmitted by a wireless node, such as every Xmilliseconds, as shown in FIG. 3B. In some aspects, an SS burst set mayhave a fixed or dynamic length, shown as Y milliseconds in FIG. 3B.

The SS burst set shown in FIG. 3B is an example of a synchronizationcommunication set, and other synchronization communication sets may beused in connection with the techniques described herein. Furthermore,the SS block shown in FIG. 3B is an example of a synchronizationcommunication, and other synchronization communications may be used inconnection with the techniques described herein.

In some aspects, an SS block includes resources that carry the PSS, theSSS, the PBCH, and/or other synchronization signals (e.g., a tertiarysynchronization signal (TSS)) and/or synchronization channels. In someaspects, multiple SS blocks are included in an SS burst, and the PSS,the SSS, and/or the PBCH may be the same across each SS block of the SSburst. In some aspects, a single SS block may be included in an SSburst. In some aspects, the SS block may be at least four symbol periodsin length, where each symbol carries one or more of the PSS (e.g.,occupying one symbol), the SSS (e.g., occupying one symbol), and/or thePBCH (e.g., occupying two symbols).

In some aspects, a synchronization communication (e.g., an SS block) mayinclude a base station synchronization communication for transmission,which may be referred to as a Tx BS-SS, a Tx gNB-SS, and/or the like. Insome aspects, a synchronization communication (e.g., an SS block) mayinclude a base station synchronization communication for reception,which may be referred to as an Rx BS-SS, an Rx gNB-SS, and/or the like.In some aspects, a synchronization communication (e.g., an SS block) mayinclude a user equipment synchronization communication for transmission,which may be referred to as a Tx UE-SS, a Tx NR-SS, and/or the like. Abase station synchronization communication (e.g., for transmission by afirst base station and reception by a second base station) may beconfigured for synchronization between base stations, and a userequipment synchronization communication (e.g., for transmission by abase station and reception by a user equipment) may be configured forsynchronization between a base station and a user equipment.

In some aspects, a base station synchronization communication mayinclude different information than a user equipment synchronizationcommunication. For example, one or more base stations synchronizationcommunications may exclude PBCH communications. Additionally, oralternatively, a base station synchronization communication and a userequipment synchronization communication may differ with respect to oneor more of a time resource used for transmission or reception of thesynchronization communication, a frequency resource used fortransmission or reception of the synchronization communication, aperiodicity of the synchronization communication, a waveform of thesynchronization communication, a beamforming parameter used fortransmission or reception of the synchronization communication, and/orthe like.

In some aspects, the symbols of an SS block are consecutive, as shown inFIG. 3B. In some aspects, the symbols of an SS block arenon-consecutive. Similarly, in some aspects, one or more SS blocks ofthe SS burst may be transmitted in consecutive radio resources (e.g.,consecutive symbol periods) during one or more subframes. Additionally,or alternatively, one or more SS blocks of the SS burst may betransmitted in non-consecutive radio resources.

In some aspects, the SS bursts may have a burst period, whereby the SSblocks of the SS burst are transmitted by the base station according tothe burst period. In other words, the SS blocks may be repeated duringeach SS burst. In some aspects, the SS burst set may have a burst setperiodicity, whereby the SS bursts of the SS burst set are transmittedby the base station according to the fixed burst set periodicity. Inother words, the SS bursts may be repeated during each SS burst set.

The base station may transmit system information, such as systeminformation blocks (SIBs) on a physical downlink shared channel (PDSCH)in certain subframes. The base station may transmit controlinformation/data on a physical downlink control channel (PDCCH) in Csymbol periods of a subframe, where B may be configurable for eachsubframe. The base station may transmit traffic data and/or other dataon the PDSCH in the remaining symbol periods of each subframe.

As indicated above, FIGS. 3A and 3B are provided as examples. Otherexamples may differ from what is described with regard to FIGS. 3A and3B.

FIG. 4 shows an example subframe format 410 with a normal cyclic prefix.The available time frequency resources may be partitioned into resourceblocks. Each resource block may cover a set of subcarriers (e.g., 12subcarriers) in one slot and may include a number of resource elements.Each resource element may cover one subcarrier in one symbol period(e.g., in time) and may be used to send one modulation symbol, which maybe a real or complex value. In some aspects, subframe format 410 may beused for transmission of SS blocks that carry the PSS, the SSS, thePBCH, and/or the like, as described herein.

An interlace structure may be used for each of the downlink and uplinkfor FDD in certain telecommunications systems (e.g., NR). For example, Qinterlaces with indices of 0 through Q−1 may be defined, where Q may beequal to 4, 6, 8, 10, or some other value. Each interlace may includesubframes that are spaced apart by Q frames. In particular, interlace qmay include subframes q, q+Q, q+2Q, etc., where q∈{0, . . . , Q−1}.

A UE may be located within the coverage of multiple BSs. One of theseBSs may be selected to serve the UE. The serving BS may be selectedbased at least in part on various criteria such as received signalstrength, received signal quality, path loss, and/or the like. Receivedsignal quality may be quantified by a signal-to-noise-and-interferenceratio (SNIR), or a reference signal received quality (RSRQ), or someother metric. The UE may operate in a dominant interference scenario inwhich the UE may observe high interference from one or more interferingBSs.

While aspects of the examples described herein may be associated with NRor 5G technologies, aspects of the present disclosure may be applicablewith other wireless communication systems. New Radio (NR) may refer toradios configured to operate according to a new air interface (e.g.,other than Orthogonal Frequency Divisional Multiple Access (OFDMA)-basedair interfaces) or fixed transport layer (e.g., other than InternetProtocol (IP)). In aspects, NR may utilize OFDM with a CP (hereinreferred to as cyclic prefix OFDM or CP-OFDM) and/or SC-FDM on theuplink, may utilize CP-OFDM on the downlink and include support forhalf-duplex operation using TDD. In aspects, NR may, for example,utilize OFDM with a CP (herein referred to as CP-OFDM) and/or discreteFourier transform spread orthogonal frequency-division multiplexing(DFT-s-OFDM) on the uplink, may utilize CP-OFDM on the downlink andinclude support for half-duplex operation using TDD. NR may includeEnhanced Mobile Broadband (eMBB) service targeting wide bandwidth (e.g.,80 megahertz (MHz) and beyond), millimeter wave (mmW) targeting highcarrier frequency (e.g., 60 gigahertz (GHz)), massive MTC (mMTC)targeting non-backward compatible MTC techniques, and/or missioncritical targeting ultra reliable low latency communications (URLLC)service.

In some aspects, a single component carrier bandwidth of 100 MHz may besupported. NR resource blocks may span 12 sub-carriers with asub-carrier bandwidth of 60 or 120 kilohertz (kHz) over a 0.1millisecond (ms) duration. Each radio frame may include 40 subframeswith a length of 10 ms. Consequently, each subframe may have a length of0.25 ms. Each subframe may indicate a link direction (e.g., DL or UL)for data transmission and the link direction for each subframe may bedynamically switched. Each subframe may include DL/UL data as well asDL/UL control data.

Beamforming may be supported and beam direction may be dynamicallyconfigured. MIMO transmissions with precoding may also be supported.MIMO configurations in the DL may support up to 8 transmit antennas withmulti-layer DL transmissions up to 8 streams and up to 2 streams per UE.Multi-layer transmissions with up to 2 streams per UE may be supported.Aggregation of multiple cells may be supported with up to 8 servingcells. Alternatively, NR may support a different air interface, otherthan an OFDM-based interface. NR networks may include entities such ascentral units or distributed units.

As indicated above, FIG. 4 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 4.

FIG. 5 illustrates an example logical architecture of a distributed RAN500, according to aspects of the present disclosure. A 5G access node506 may include an access node controller (ANC) 502. The ANC may be acentral unit (CU) of the distributed RAN 500. The backhaul interface tothe next generation core network (NG-CN) 504 may terminate at the ANC.The backhaul interface to neighboring next generation access nodes(NG-ANs) may terminate at the ANC. The ANC may include one or more TRPs508 (which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs,gNB, or some other term). As described above, a TRP may be usedinterchangeably with “cell.”

The TRPs 508 may be a distributed unit (DU). The TRPs may be connectedto one ANC (ANC 502) or more than one ANC (not illustrated). Forexample, for RAN sharing, radio as a service (RaaS), and servicespecific AND deployments, the TRP may be connected to more than one ANC.A TRP may include one or more antenna ports. The TRPs may be configuredto individually (e.g., dynamic selection) or jointly (e.g., jointtransmission) serve traffic to a UE.

The local architecture of RAN 500 may be used to illustrate fronthauldefinition. The architecture may be defined that support fronthaulingsolutions across different deployment types. For example, thearchitecture may be based at least in part on transmit networkcapabilities (e.g., bandwidth, latency, and/or jitter).

The architecture may share features and/or components with LTE.According to aspects, the next generation AN (NG-AN) 510 may supportdual connectivity with NR. The NG-AN may share a common fronthaul forLTE and NR.

The architecture may enable cooperation between and among TRPs 508. Forexample, cooperation may be preset within a TRP and/or across TRPs viathe ANC 502. According to aspects, no inter-TRP interface may beneeded/present.

According to aspects, a dynamic configuration of split logical functionsmay be present within the architecture of RAN 500. The packet dataconvergence protocol (PDCP), radio link control (RLC), media accesscontrol (MAC) protocol may be adaptably placed at the ANC or TRP.

According to various aspects, a BS may include a central unit (CU)(e.g., ANC 502) and/or one or more distributed units (e.g., one or moreTRPs 508).

As indicated above, FIG. 5 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 5.

FIG. 6 illustrates an example physical architecture of a distributed RAN600, according to aspects of the present disclosure. A centralized corenetwork unit (C-CU) 602 may host core network functions. The C-CU may becentrally deployed. C-CU functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 604 may host one or more ANC functions.Optionally, the C-RU may host core network functions locally. The C-RUmay have distributed deployment. The C-RU may be closer to the networkedge.

A distributed unit (DU) 606 may host one or more TRPs. The DU may belocated at edges of the network with radio frequency (RF) functionality.

As indicated above, FIG. 6 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 6.

FIG. 7 is a diagram illustrating an example 700 of reference pointdetermination, in accordance with various aspects of the presentdisclosure. As shown in FIG. 7, example 700 includes a BS 110 and a UE120.

As further shown in FIG. 7, and by reference numbers 710 and 720, BS 110may transmit an indication of an indexing configuration for thefrequency domain to UE 120, and UE 120 may receive the indication. Forexample, based at least in part on detecting a triggering event, BS 110may transmit the indication of the indexing configuration to UE 120. Insome aspects, the triggering event may include a handover, a secondarycell configuration (e.g., in a carrier aggregation scenario), a primarysecondary cell configuration (e.g., in a dual-connectivity scenario), abandwidth part configuration, and/or the like. For example, based atleast in part on determining that the UE is handed over from a firstcell to a second cell, BS 110 may determine to provide the indication ofthe indexing configuration to resolve an ambiguity in physical resourceblock indexing for UE 120.

In some aspects, BS 110 may configure physical resource block indexingbased at least in part on a presence of a synchronization sequence orphysical broadcast channel (SS/PBCH) block. For example, when acomponent carrier for UE 120 does not include the SS/PBCH block, BS 110may configure physical resource block indexing based at least in part ona reference point, which may be determined based at least in part on anabsolute reference point (e.g., a reference point A, which may be termed‘Point A’). Additionally, or alternatively, when the component carrierincludes the SS/PBCH block, BS 110 may configure physical resource blockindexing based at least in part on a reference point, which may bedetermined based at least in part on a start of a CORESET.

In this way, BS 110 reduces a likelihood of a communication interruptionand/or a negative impact to network performance relative to theambiguity resulting in UE 120 failing to successfully decodetransmission from BS 110, failing to successfully transmit to UE 120,and/or the like.

As further shown in FIG. 7, and by reference numbers 730 and 740, UE 120may determine communication parameters, and may communicate based atleast in part on the communication parameters. For example, based atleast in part on the indication of the indexing configuration, UE 120may determine physical resource block indexing of a relative referencepoint (e.g., a reference point) relative to an absolute reference point(e.g., reference point A or Point A) (e.g., a global physical resourceblock indexing scenario). Additionally, or alternatively, UE 120 maydetermine physical resource block indexing relative to a start of aCORESET (e.g., a local physical resource block indexing scenario). Insome aspects, UE 120 may determine a set of physical resource blocks(PRBs) allocated for a bandwidth part based at least in part ondetermining the physical resource block indexing relative to, forexample, an absolute reference point (e.g., reference point A).

In some aspects, UE 120 may configure a communication parameter relatingto a radio resource management measurement. For example, for anintra-frequency radio resource management measurement, UE 120 maydetermine that a set of channel state information reference signal(CSI-RS) sequences for a serving cell, a neighbor cell, and/or the likeis defined based at least in part on the absolute reference point forthe serving cell. Additionally, or alternatively, UE 120 may determinethe absolute reference point for CSI-RSs for an intra-frequency radioresource management measurement. In some aspects, UE 120 may determinean absolute reference point, for the intra-frequency radio resourcemanagement measurement, on a per frequency layer basis (e.g., for a setof cells associated with a common carrier frequency), and maycommunicate with BS 110 to enable the radio resource managementmeasurement. Additionally, or alternatively, UE 120 may determine anabsolute reference point, for the intra-frequency radio resourcemanagement measurement, on a per frequency band basis.

Additionally, or alternatively, UE 120 may determine to use a servingcell absolute reference point for an inter-frequency radio resourcemanagement measurement. In some aspects, UE 120 may determine anabsolute reference point for a radio resource management measurementbased at least in part on an absolute channel number (e.g., based atleast in part on receiving a UE-specific radio resource controlconfiguration message), based at least in part on an SS/PBCH blockfrequency, and/or the like. In some aspects, UE 120 may determine anabsolute reference point based at least in part on a radio resourcecontrol configuration identifying a set of candidate absolute referencepoint's for a cell and based at least in part on another radio resourcecontrol configuration message indicating a particular candidate absolutereference point for UE 120. In this case, based at least in part ondetermining an absolute reference point, UE 120 may determine acommunication structure (e.g., a CSI-RS sequence, a physical resourceblock index start, and/or the like), and may communicate with BS 110.

As indicated above, FIG. 7 is provided as an example. Other examples maydiffer from what is described with respect to FIG. 7.

FIG. 8 is a diagram illustrating an example process 800 performed, forexample, by a UE, in accordance with various aspects of the presentdisclosure. Example process 800 is an example where a UE (e.g., UE 120and/or the like) performs operations associated with reference pointdetermination.

As shown in FIG. 8, in some aspects, process 800 may include receiving,from a base station and based at least in part on a triggering event, anindication of a frequency domain indexing configuration for a relativereference point (block 810). For example, the UE (e.g., using receiveprocessor 258, transmit processor 264, controller/processor 280, memory282, and/or the like) may receive, from a base station and based atleast in part on a triggering event, an indication of a frequency domainindexing configuration for a relative reference point, as describedabove. In some aspects, the relative reference point may be referred toas ‘the reference point’ and may be a reference point for a timingparameter k.

As further shown in FIG. 8, in some aspects, process 800 may includeusing at least one of a start of a control resource set or an absolutereference point for the relative reference point based at least in parton the indication of the frequency domain indexing configuration (block820). For example, the UE (e.g., using receive processor 258, transmitprocessor 264, controller/processor 280, memory 282, and/or the like)may use at least one of a start of a control resource set or an absolutereference point for the relative reference point based at least in parton the indication of the frequency domain indexing configuration, asdescribed above.

Process 800 may include additional aspects, such as any singleimplementation or any combination of aspects described below and/or inconnection with one or more other processes described elsewhere herein.

In a first aspect, process 800 may include communicating using aphysical channel or signal determined based at least in part on therelative reference point.

In a second aspect, alone or in combination with the first aspect, thephysical channel is at least one of a physical broadcast channel (PBCH),a physical downlink control channel (PDCCH), a physical downlink sharedchannel (PDSCH), a physical uplink control channel (PUCCH), a physicaluplink shared channel (PUSCH), a sounding reference signal (SRS), or achannel state information reference signal (CSI-RS). In a third aspect,alone or in combination with any one or more of the first and secondaspects, the relative reference point is physical resource block 0 of aninitial downlink bandwidth part for the control resource set. In someaspects, the control resource set is configured by a physical channel.

In a fourth aspect, alone or in combination with any one or more of thefirst through third aspects, the control resource set is controlresource set 0 and the relative reference point is the start of thecontrol resource set. In a fifth aspect, alone or in combination withany one or more of the first through fourth aspects, the controlresource set is not control resource set 0 and the relative referencepoint is the absolute reference point. In a sixth aspect, alone or incombination with any one or more of the first through fifth aspects, therelative reference point is determined based at least in part on whethera configured bandwidth part or the control resource set is associatedwith an initial access procedure.

In a seventh aspect, alone or in combination with any one or more of thefirst through sixth aspects, the triggering event includes at least oneof a handover, a secondary cell configuration, a primary secondary cellconfiguration, or a bandwidth part configuration. In an eighth aspect,alone or in combination with any one or more of the first throughseventh aspects, the relative reference point is determined based atleast in part on a component carrier not being associated with asynchronization sequence or physical broadcast channel (SS/PBCH) block.In a ninth aspect, alone or in combination with any one or more of thefirst through eighth aspects, the absolute reference point of a servingcell defines, for an intra-frequency radio resource managementmeasurement, a channel state information reference signal sequence.

In a tenth aspect, alone or in combination with any one or more of thefirst through ninth aspects, for an inter-frequency radio resourcemanagement measurement, the absolute reference point is defined on a perfrequency layer basis or a per frequency band basis. In an eleventhaspect, alone or in combination with any one or more of the firstthrough tenth aspects, for an inter-frequency radio resource managementmeasurement, the absolute reference point is defined based at least inpart on a serving cell of the UE or a neighbor cell of the UE. In atwelfth aspect, alone or in combination with any one or more of thefirst through eleventh aspects, the absolute reference point is definedbased at least in part on a radio resource control configuration messageand using an absolute channel number.

In a thirteenth aspect, alone or in combination with any one or more ofthe first through twelfth aspects, the absolute reference point isdefined based at least in part on a per frequency layer basis and usingan absolute channel number. In a fourteenth aspect, alone or incombination with any one or more of the first through thirteenthaspects, the absolute reference point is defined based at least in parton a radio resource control configuration message and relative to asynchronization sequence or physical broadcast channel (SS/PBCH) blockfrequency. In a fifteenth aspect, alone or in combination with any oneor more of the first through fourteenth aspects, the absolute referencepoint is defined based at least in part on a candidate absolutereference point of a set of candidate absolute reference points.

Although FIG. 8 shows example blocks of process 800, in some aspects,process 800 may include additional blocks, fewer blocks, differentblocks, or differently arranged blocks than those depicted in FIG. 8.Additionally, or alternatively, two or more of the blocks of process 800may be performed in parallel.

The foregoing disclosure provides illustration and description, but isnot intended to be exhaustive or to limit the aspects to the preciseform disclosed. Modifications and variations are possible in light ofthe above disclosure or may be acquired from practice of the aspects.

As used herein, the term component is intended to be broadly construedas hardware, firmware, or a combination of hardware and software. Asused herein, a processor is implemented in hardware, firmware, or acombination of hardware and software.

Some aspects are described herein in connection with thresholds. As usedherein, satisfying a threshold may refer to a value being greater thanthe threshold, greater than or equal to the threshold, less than thethreshold, less than or equal to the threshold, equal to the threshold,not equal to the threshold, and/or the like.

It will be apparent that systems and/or methods, described herein, maybe implemented in different forms of hardware, firmware, or acombination of hardware and software. The actual specialized controlhardware or software code used to implement these systems and/or methodsis not limiting of the aspects. Thus, the operation and behavior of thesystems and/or methods were described herein without reference tospecific software code—it being understood that software and hardwarecan be designed to implement the systems and/or methods based, at leastin part, on the description herein.

Even though particular combinations of features are recited in theclaims and/or disclosed in the specification, these combinations are notintended to limit the disclosure of possible aspects. In fact, many ofthese features may be combined in ways not specifically recited in theclaims and/or disclosed in the specification. Although each dependentclaim listed below may directly depend on only one claim, the disclosureof possible aspects includes each dependent claim in combination withevery other claim in the claim set. A phrase referring to “at least oneof” a list of items refers to any combination of those items, includingsingle members. As an example, “at least one of: a, b, or c” is intendedto cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combinationwith multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c,a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering ofa, b, and c).

No element, act, or instruction used herein should be construed ascritical or essential unless explicitly described as such. Also, as usedherein, the articles “a” and “an” are intended to include one or moreitems, and may be used interchangeably with “one or more.” Furthermore,as used herein, the terms “set” and “group” are intended to include oneor more items (e.g., related items, unrelated items, a combination ofrelated and unrelated items, etc.), and may be used interchangeably with“one or more.” Where only one item is intended, the term “one” orsimilar language is used. Also, as used herein, the terms “has,” “have,”“having,” and/or the like are intended to be open-ended terms. Further,the phrase “based on” is intended to mean “based, at least in part, on”unless explicitly stated otherwise.

What is claimed is:
 1. A method of wireless communication performed by auser equipment (UE), comprising: receiving, from a base station andbased at least in part on a triggering event, an indication of afrequency domain indexing configuration for a relative reference pointfor a communication, wherein the triggering event includes a handover;determining whether a component carrier of the communication includes asynchronization sequence and physical broadcast channel (SS/PBCH) block;determining the relative reference point based at least on theindication of the frequency domain indexing configuration, on a start ofcontrol resource set in response to the component carrier including theSS/PBCH block, and on an absolute reference point in response to thecomponent carrier not including the SS/PBCH block; and communicating thecommunication based at least in part on the relative reference point. 2.The method of claim 1, wherein the communication uses a physical channelthat is at least one of: a physical broadcast channel (PBCH), a physicaldownlink control channel (PDCCH), a physical downlink shared channel(PDSCH), a physical uplink control channel (PUCCH), a physical uplinkshared channel (PUSCH), a sounding reference signal (SRS), or a channelstate information reference signal (CSI-RS).
 3. The method of claim 1,wherein the relative reference point is physical resource block 0 of aninitial downlink bandwidth part for the control resource set, andwherein the control resource set is configured by a physical channel. 4.The method of claim 1, wherein the control resource set is controlresource set 0 and the relative reference point is the start of thecontrol resource set.
 5. The method of claim 1, wherein the controlresource set is not control resource set 0 and the relative referencepoint is the absolute reference point.
 6. The method of claim 1, whereinthe relative reference point is determined based at least in part onwhether a configured bandwidth part or the control resource set isassociated with an initial access procedure.
 7. The method of claim 1,wherein the absolute reference point of a serving cell defines, for anintra-frequency radio resource management measurement, a channel stateinformation reference signal sequence.
 8. The method of claim 1,wherein, for an inter-frequency radio resource management measurement,the absolute reference point is defined on a per frequency layer basisor a per frequency band basis.
 9. The method of claim 1, wherein, for aninter-frequency radio resource management measurement, the absolutereference point is defined based at least in part on a serving cell ofthe UE or a neighbor cell of the UE.
 10. The method of claim 1, whereinthe absolute reference point is defined based at least in part on aradio resource control configuration message and using an absolutechannel number.
 11. The method of claim 1, wherein the absolutereference point is defined based at least in part on a per frequencylayer basis and using an absolute channel number.
 12. The method ofclaim 1, wherein the absolute reference point is defined based at leastin part on a radio resource control configuration message.
 13. Themethod of claim 1, wherein the absolute reference point is defined basedat least in part on a candidate of a set of candidate absolute referencepoints.
 14. The method of claim 1, wherein determining whether thecomponent carrier includes the SS/PBCH block comprises: determining thatthe component carrier does not include the SS/PBCH block, and whereindetermining the relative reference point comprises: determining therelative reference point based on the component carrier not includingthe SS/PBCH block.
 15. A user equipment (UE) for wireless communication,comprising: a memory; and one or more processors operatively coupled tothe memory, the one or more processors configured to: receive, from abase station and based at least in part on a triggering event, anindication of a frequency domain indexing configuration for a relativereference point for a communication, wherein the triggering eventincludes a handover; determine whether a component carrier of thecommunication includes a synchronization sequence and physical broadcastchannel (SS/PBCH) block; determine the relative reference point based atleast on the indication of the frequency domain indexing configuration,on a start of a control resource set in response to the componentcarrier including the SS/PBCH block, and on an absolute reference pointin response to the component carrier not including the SS/PBCH block;and communicate the communication based at least in part on the relativereference point.
 16. The UE of claim 15, wherein the communication usesa physical channel that is at least one of: a physical broadcast channel(PBCH), a physical downlink control channel (PDCCH), a physical downlinkshared channel (PDSCH), a physical uplink control channel (PUCCH), aphysical uplink shared channel (PUSCH), a sounding reference signal(SRS), or a channel state information reference signal (CSI-RS).
 17. TheUE of claim 15, wherein the absolute reference point is physicalresource block 0 of an initial downlink bandwidth part for the controlresource set, and wherein the control resource set is configured by aphysical channel.
 18. The UE of claim 15, wherein the control resourceset is control resource set 0 and the relative reference point is thestart of the control resource set.
 19. The UE of claim 15, wherein thecontrol resource set is not control resource set 0 and the relativereference point is the absolute reference point.
 20. The UE of claim 15,wherein the relative reference point is determined based at least inpart on whether a configured bandwidth part or the control resource setis associated with an initial access procedure.
 21. The UE of claim 15,wherein, to determine whether the component carrier includes the SS/PBCHblock, the one or more processors are configured to: determine that thecomponent carrier does not include the SS/PBCH block, and wherein, todetermine the relative reference point, the one or more processors areconfigured to: determine the relative reference point based on thecomponent carrier not including the SS/PBCH block.
 22. A non-transitorycomputer-readable medium storing one or more instructions for wirelesscommunication, the one or more instructions comprising: one or moreinstructions that, when executed by one or more processors of a userequipment (UE), cause the one or more processors to: receive, from abase station and based at least in part on a triggering event, anindication of a frequency domain indexing configuration for a relativereference point for a communication, wherein the triggering eventincludes a handover; determine whether a component carrier of thecommunication includes a synchronization sequences and physicalbroadcast channel (SS/PBCH) block; determine the relative referencepoint based at least on the indication of the frequency domain indexingconfiguration, on a start of a control resource set in response to thecomponent carrier including the SS/PBCH block, and on an absolutereference point in response to the component carrier no including theSS/PBCH block; and communicate the communication based at least in parton the relative reference point.
 23. The non-transitorycomputer-readable medium of claim 22, wherein the communication uses aphysical channel that is at least one of: a physical broadcast channel(PBCH), a physical downlink control channel (PDCCH), a physical downlinkshared channel (PDSCH), a physical uplink control channel (PUCCH), aphysical uplink shared channel (PUSCH), a sounding reference signal(SRS), or a channel state information reference signal (CSI-RS).
 24. Thenon-transitory computer-readable medium of claim 22, wherein theabsolute reference point is physical resource block 0 of an initialdownlink bandwidth part for the control resource set, and wherein thecontrol resource set is configured by a physical channel.
 25. Thenon-transitory computer-readable medium of claim 22, wherein the controlresource set is control resource set 0 and the relative reference pointis the start of the control resource set.
 26. An apparatus for wirelesscommunication, comprising: means for receiving, from a base station andbased at least in part on a triggering event, an indication of afrequency domain indexing configuration for a relative reference pointfor a communication, wherein the triggering event includes a handover;means for determining whether a component carrier on the communicationincludes a synchronization sequence and physical broadcast channel(SS/PBCH) block; means for determining the relative reference pointbased at least on the indication of the frequency domain indexingconfiguration, on a start of a control resource set in response to thecomponent carrier including the SS/PBCH block, an on an absolutereference point in response to the component carrier not including theSS/PBCH block; and means for communicating the communication based atleast in part on the relative reference point.
 27. The apparatus ofclaim 26, wherein the communication uses a physical channel that is atleast one of: a physical broadcast channel (PBCH), a physical downlinkcontrol channel (PDCCH), a physical downlink shared channel (PDSCH), aphysical uplink control channel (PUCCH), a physical uplink sharedchannel (PUSCH), a sounding reference signal (SRS), or a channel stateinformation reference signal (CSI-RS).
 28. The apparatus of claim 26,wherein the absolute reference point is physical resource block 0 of aninitial downlink bandwidth part for the control resource set, andwherein the control resource set is configured by a physical channel.29. The apparatus of claim 26, wherein the control resource set iscontrol resource set 0 and the relative reference point is the start ofthe control resource set.